POSIX Thread Help Post: 302550713

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Top Forums Programming POSIX Thread Help Post 302550713 by pharaoh on Friday 26th of August 2011 09:15:46 PM

08-26-2011

Registered User

POSIX Thread Help

I want to create a program that creates 2 child process, and each of them creates 2 threads, and each thread prints its thread id. I0ve allread done that the outuput isn't the outuput i want.
When a run the following comand "$./a.out | sort -u | wc -l" I have the folowing output
2
$:
It should be 6.
Thanks in advance

Code:

#include <stdio.h>
#include <sys/types.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>

#include "debug.h"

#define FFORK 1
#define FTHRE 2

void* identify(void *arg);

int main(int argc, char *argv[]){

     pthread_t th_id[2];
     short int i = 0;

     (void)argc; (void)argv;
     setvbuf(stdout,NULL,_IONBF,0);

     switch (fork()){
          case -1:
               ERROR(FFORK,"Fork Failed\n"); 
          break;

          case 0:
               if (pthread_create(&th_id[0],NULL,identify,NULL) != 0 || pthread_create(&th_id[1],NULL,identify,NULL) != 0)
                    ERROR(FTHRE,"FTHRE\n");            
               if (pthread_join(th_id[0],NULL) != 0 || pthread_join(th_id[1],NULL) != 0)
                    ERROR(FTHRE,"FTHRE\n");
               exit(0);
          break;

          default:
               switch(fork()){
                    case -1:
                         ERROR(FFORK,"FFORK\n");
                    break;
        
                    case 0:            
                         if (pthread_create(&th_id[0],NULL,identify,NULL) != 0  || pthread_create(&th_id[1],NULL,identify,NULL) != 0)
                              ERROR(FTHRE,"FTHRE\n");            
                         if (pthread_join(th_id[0],NULL) != 0 || pthread_join(th_id[1],NULL) != 0)
                              ERROR(FTHRE,"FTHRE\n");
                         exit(0);
                    break;
        
                    default:
                         switch(fork()){
                              case -1:
                                   ERROR(FFORK,"FFORK\n");
                              break;
            
                              case 0:            
                                   if (pthread_create(&th_id[0],NULL,identify,NULL)  != 0 || pthread_create(&th_id[1],NULL,identify,NULL) != 0)
                                        ERROR(FTHRE,"FTHRE\n");                        
                                    if (pthread_join(th_id[0],NULL) != 0 || pthread_join(th_id[1],NULL) != 0)
                                         ERROR(FTHRE,"FTHRE\n");
                                    exit(0);
                              break;
                
                              default:
                                   for (i=0;i < 3; i++)
                                        wait(NULL);
                         }          
               }
     }

     return 0;
}

void* identify(void *arg){
    (void) arg;
     printf("%lu\n", (unsigned long int)pthread_self());
     pthread_exit(NULL);
}

Last edited by pharaoh; 08-28-2011 at 01:02 PM..

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LEARN ABOUT OPENSOLARIS

pthread_join

pthread_join(3C)					   Standard C Library Functions 					  pthread_join(3C)

NAME

       pthread_join - wait for thread termination

SYNOPSIS

       cc -mt [ flag... ] file... -lpthread [ library... ]
       #include <pthread.h>

       int pthread_join(pthread_t thread, void **status);

DESCRIPTION

       The  pthread_join()  function  suspends	processing of the calling thread until the target thread completes. thread must be a member of the
       current process and it cannot be a detached thread. See pthread_create(3C).

       If two or more threads wait for the same thread to complete, all will suspend processing until the thread  has  terminated,  and  then  one
       thread will return successfully and the others will return with an error of ESRCH. The pthread_join() function will not block processing of
       the calling thread if the target thread has already terminated.

       If a pthread_join() call returns successfully with a non-null status argument, the value passed	to  pthread_exit(3C)  by  the  terminating
       thread will be placed in the location referenced by status.

       If  the	pthread_join()	calling  thread  is cancelled, then the target thread will remain joinable by pthread_join(). However, the calling
       thread may set up a cancellation cleanup handler on thread prior to  the  join  call,  which  may  detach  the  target  thread  by  calling
       pthread_detach(3C). See pthread_detach(3C) and pthread_cancel(3C).

RETURN VALUES

       If successful, pthread_join() returns 0. Otherwise, an error number is returned to indicate the error.

ERRORS

       EDEADLK	  A joining deadlock would occur, such as when a thread attempts to wait for itself.

       EINVAL	  The thread corresponding to the given thread ID is a detached thread.

       ESRCH	  No thread could be found corresponding to the given thread ID.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       pthread_cancel(3C), pthread_create(3C), pthread_detach(3C), pthread_exit(3C), wait(3C), attributes(5), standards(5)

NOTES

       The pthread_join(3C) function must specify the thread ID for whose termination it will wait.

       Calling	pthread_join()	also  "detaches"  the  thread;	that is, pthread_join() includes the effect of the pthread_detach() function. If a
       thread were to be cancelled when blocked in pthread_join(), an explicit detach would have to be performed in the cancellation cleanup  han-
       dler. The pthread_detach() function exists primarily for this purpose.

SunOS 5.11							    23 Mar 2005 						  pthread_join(3C)